Originally Posted by
dutret
Most frames with horizontal dropouts are steel. You can just compress them down 6mms. Otherwise the majority of formula wheelsets available for cheap have long enough axles to add a few washers and space out to 126 or 130.
But the OP said he's going to use a Specialized Allez - which, unless it's really old, has alumnium dropouts. I'd be worried about compressing them, and the stays, which would be aluminium, too.
The spacer idea is a good one. Although, on my old Dura-Ace hubs I ran out of thread for the bolt and could only widen them to about 125 or 126mm. It helped though.